Drone cells are becoming a reality

Back in early 2015, the then EE CEO Olaf Swantee said, "We will begin exploring 'Air Masts', essentially aerial small cells positioned in the sky above a hard-to-reach area, using either tethered balloons or unmanned craft, bridging the UK's transmission gap."

The vision has not changed a lot. I recently blogged about 'EE's vision of Ultra-Reliable Emergency Network'. If you look at the slide above you will notice temporary solutions include Air masts, UAV's and Network in a box (NIB).

Nokia recently did a trial with EE where they used a drone to carry a tiny base station to remote areas around Inverness. Weighing in at only 2 kg, the Nokia Flexi Zone Pico cell has all the punch of LTE in a very compact package, allowing 4G services to be provided wherever a drone can reach. High quality LTE voice calls between responders, video streaming and up to 150 Mbps data throughput were all achieved, with no need for a connection to an external core network.

While it doesn't exactly say the area that was covered, I would expect it to be able to do at least 1 km diameter to be effective in an emergency scenario.

According to a recent International Business Times article, US operator AT&T is trying something similar to deal with the struggle to provide enough wireless data are large venue events to please customers. The mobile operator says that drones known as "Flying Cell on Wings (COWs)" could make all the difference. The idea would be that the drone would be tethered to the ground so they would hover in one place, sort of like a portable hovering small cell. 

Finally, Ericsson and China Mobile conduct world’s first 5G drone prototype field trial. In their recent press release it says:

In the trial, held in Wuxi in China’s Jiangsu province, a drone was flown using operator’s cellular network with 5G-enabled technologies and with handovers across multiple sites. In order to demonstrate the concept’s validity in a real-world setting, the handovers were performed between sites that were simultaneously in use by commercial mobile phone users.

The potential use cases for this technology include mission-critical applications such as support for emergency services. However, end-to-end low latency needs to be guaranteed by the operator’s network to ensure the safety and reliability of such services.

I am sure we will be hearing more on this topic soon.

Case Study: Deploying small cell backhaul in China

Came across this old presentation (embedded below) by CCS (Cambridge Communication Systems Limited) of small cell backhaul deployment in China. Having looked at their website they do have regular updates for different deployment. Here is one with China Mobile and here is another one from China Telecom. Interested readers can also read their regular updates here.

Here is their presentation from Small Cells World Summit (Backhaul Summit) from last year:

Super Macros and HetNets

The other day I read the following on Light Reading:

UK operator EE wants to turn its existing macro cell sites into "super macros," according to Andy Sutton, the carrier's principal network architect, speaking at the recent Base Station conference in London.

EE 's plan to super size its macro cell sites fits in to a broader Heterogeneous Network (HetNet) strategy for adding capacity and extending coverage. The operator rolled out the first LTE network in the UK last year, and has now covered 55 percent of the UK population and has 1 million 4G customers.

"Super macro is the first step toward building a HetNet,” said Sutton. “Evolving the macro is the most cost-optimized way to adding capacity into our networks."

But what makes a macro super?

According to Sutton, a super macro would typically have multiple radio access technologies (RAT), three-to-six base station sectors, and operate in multiple frequency bands using carrier aggregation techniques. It could be a standalone base station or a hub for subtended, smaller micro cells. He added that infrastructure sharing is vital to the strategy as well.

Once the operator has sufficiently beefed up its macro cell sites, then it can look to smaller cells to be deployed indoors and outdoors in hotspots or cell edge locations. Sutton described a small cell deployment as an "underlay" to the super macro.

The term super macro isn't exactly new, but the fact that operators are talking about it now indicates just how much more they are looking to do with their existing radio access network (RAN) infrastructure before introducing new small cells or while planning a small cell deployment.

"Within the super macro concept, there's quite a lot operators can do to improve performance," says Heavy Reading senior analyst Gabriel Brown.

Along with adding sectors, using more spectrum bands, or employing carrier aggregation, Brown also includes in the super macro concept using 4x4 and 8x8 MIMO, active antenna systems, vertical sectorization, or beamforming.

The advantage of improving macro sites is that many of the basic elements that go into the total cost of ownership of a cell site are already in place, such as power, real estate rental, and backhaul, according to Brown.

I remember the folks from Ericsson mentioning about Super macros but I had not given any thoughts to it. Well, I went back to see what they have been talking about and found this:

Since it was not very clear, I found some additional information from an NGMN presentation as follows:

China Mobile's Nanocell

China Mobile prefers to call its Small Cell, Nanocell. I found an interesting summary on this topic from Rupert Baines in the OSP Magazine, some of this information is copied below.

Nanocell is defined by the China Mobile Research Institute (CMRI) as follows: “An integrated Small cell supporting GSM / TD-SCDMA / TD-LTE standards and WLAN (WiFi) solutions. With the key feature of supporting both wireless network and WLAN (WiFi) services, it can be deployed in enterprise, home and high capacity hotspot locations. It also uses standard broadband connection as a low-cost network backhaul, hence reducing deployment and maintenance cost while providing advanced and reliable security features.”

'China Mobile' and 'Ericsson' deploy GSM Picocell/Metrocell in Nanning, the capital of China's Guangxi region

While the whole world has been focussing on HSPA+ and LTE small cells, a recent press release from Ericsson told us about GSM based 'City Site' deployed in Nanning. From the press release:

Currently, China’s urban construction is in full swing, and its mobile network coverage is rising. In the increasingly crowded urban environment, however, ensuring the quality of mobile-network coverage has become a problem.

In order to meet this challenge, Ericsson has launched the City Site integrated solution, and successfully applied it to China Mobile’s GSM network in Nanning, Guangxi. The City Site, which has been deployed with the standard RBS6601 base station, has an integrated Omni Antenna, which only covers a small area and is, therefore, easy to deploy. It could also be launched with just access to power and transmission cables.

According to the test of the live network, the City Site has effectively met the capacity and quality needs of network coverage, as well as ensuring excellent user experience.

Are we going to see more of Cloud RAN (C-RAN) in future?

China Mobile was in news a few times the last month with regards to Metrocells and C-RAN. The first item from TelecomAsia:

Alcatel-Lucent has unveiled a new TD-LTE metro base station for its lightRadio product line that will be deployed by China Mobile, which co-developed it.

 

The compact lightRadio Metro Radio – revealed at this year’s Mobile World Congress in Barcelona – houses two lightRadio cubes, fully integrated with a directional antenna, with an output of 5W.

 

Alcatel-Lucent says the design allows it to “provide the coverage normally associated with a much bulkier, heavier remote radio unit linked to an external antenna via an RF coaxial cable.”

 

China Mobile will deploy the 2.6 GHz Metro Radio in its TD-LTE network in Shanghai, Nanjing and Qingdao – specifically, in busy indoor and outdoor locations like shopping centers where macro coverage can suffer either from building density or too many people trying to access the network.

 

The Metro Radio is the first product to result from a co-creation agreement signed by Alcatel-Lucent and China Mobile just over a year ago to conduct joint development and test activities on lightRadio TD-LTE projects.

An article on the same topic in Rethink-wireless throws a bit more light:

The TDD lightRadio Metro Radio houses two of ALU's now-famous 'cubes' (highly compact radios which can be installed on lamp posts) integrated with a directional antenna. This enables a level of coverage which would normally require a far larger remote radio unit linked to an external antenna via cable, claimed ALU.

China Mobile's first trial TD-LTE network using the lightRadio product covers 13 cities including Shanghai, Nanjing and Qingdao. The base station will be deployed in busy indoor and outdoor locations, such as retail malls and sports stadia. As well as C-RAN, Mobile also plans to deploy compact metrocells combining 3G, 4G and Wi-Fi on a massive scale in future.

Another one:

ASOCS Ltd., a Silicon IP provider of software defined radio solutions and CMRI, Research Institute of China Mobile (CMCC) Ltd., the world's largest mobile operator, have signed a strategic memorandum of understanding for the joint development, commercialization, testing and deployment of large-scale baseband processing units for China Mobile's next generation Cloud-RAN network.

Earlier trials undertaken by leading mobile operators, identified the bottleneck of Centralized Base-band Units, consisting of general purpose CPU, to perform major baseband calculations in cost and power efficient management. The solution was to introduce significant offloading capabilities of such calculations with highly specialized Modem Processing Units (MPU).

Today there is a growing understanding in the industry that such MPU should support a wide range of system partitioning, topologies and real time system performance, including large scale Collaborative Multi-point communications (COMP) and massive MIMO. Since communication algorithms are evolving over time, and since the C-RAN concept provisions on-the-fly reconfiguration of the BBU to support a variety of mobile communication standards, an MPU solution which is re-configurable at runtime has a great advantage over traditional hard-wired designs.

China Mobile (CMCC) has been pushing the cloud agenda for a long time. A whitepaper from them on the same topic is available here.

Picture source: NTT Docomo press release

NTT Docomo is another operator who believes very much in C-RAN. Occasionally it refers to the C-RAN as Centralized RAN. There were couple of announcements from their side:

The first one was a press release from Docomo here:

NTT DOCOMO, INC., Japan’s leading mobile operator and provider of integrated services centered on mobility, announced today it will begin developing high-capacity base stations built with advanced C-RAN architecture for DOCOMO’s coming next-generation LTE-Advanced (LTE-A) mobile system. The new architecture will enable quick, efficient deployment of base stations, especially in high-traffic areas such as train stations and large commercial facilities, for significantly improved data capacity and throughput.

Advanced C-RAN architecture, a brand new concept proposed by DOCOMO, will enable small “add-on” cells for localized coverage to cooperate with macro cells that provide wider area coverage. This will be achieved with carrier aggregation technology, one of the main LTE-Advanced technologies standardized by the Third Generation Partnership Project (3GPP). The small add-on cells will significantly increase throughput and system capacity while maintaining mobility performance provided by the macro cell.

High-capacity base stations utilizing advanced C-RAN architecture will serve as master base stations both for multiple macro cells covering broad areas and for add-on cells in smaller, high-traffic areas. The base stations will accommodate up to 48 macro and add-on cells at launch and even more later. Carrier aggregation will be supported for cells served by the same base station, enabling the flexible deployment of add-on cells. In addition, maximum downlink throughput will be extendible to 3Gbps, as specified by 3GPP standards.

Another one from Rethink-wireless here:

Japan's Docomo has selected the vendors, Nokia Siemens and Panasonic, which will upgrade its network with certain LTE-A features like carrier aggregation.

This is a good win for NSN, which has not featured as heavily as Ericsson and Alcatel-Lucent in the most advanced LTE roll-outs to date. Breaking into the Japanese carriers is tough, since Docomo in particular tends to rely on trusted local suppliers with which it has long-standing development alliances.

Panasonic, of course, falls into that category - it has worked with the operator since 2007 on LTE network infrastructure, but NSN was also brought into that project at an early stage and its efforts have borne fruit. The European vendor will supply its Liquid Radio multiple standard RAN. Like Docomo's LTE network, there will be heavy use of remote radio heads, with baseband processing virtualized in the cloud, as well as increasing roll-out of small cells to increase indoor and outdoor capacity. NSN says the base stations will deliver capacity of 300Mbps.

In future, the two vendors will support Docomo's own particular definition of Cloud-RAN, a concept which is being pioneered in China, Japan and South Korea, and which takes the idea of remote radio heads and shared basebands to a new level. Docomo says it favors C-RAN because the cell site equipment, consisting of radio and antenna, is compact and low power, and so can be deployed quickly in high traffic areas like train stations. It calls its architecture Advanced C-RAN and this will rely on some HetNet principles, including a separate layer of 'add-on' small cells adding localized capacity while cooperating with macrocells.

In the C-RAN, there will be high capacity master base stations supporting multiple macrocells plus the local small cells. The master BTSs will handle up to 48 macro and small cells at launch and more later. Carrier aggregation will be supported for cells served by the same base station. The carrier says it will boost peak downlink speed to 3Gbps over time, hitting 'true 4G' and 3GPP LTE-B standards.

If you are wondering what 'LTE-B' or the 'true 4G' is, see this post here.

In South Korea, both KT and SK Telecom have announced C-RAN strategies for their LTE deployments, dubbed Cloud Communications Center (CCC) and Smart Cloud Access Network (SCAN) respectively. As early as June 2011, SKT had deployed 1,772 RRHs and 609 baseband units within its LTE network in capital Seoul. The lower amount of baseband units suggests an average of almost three RRHs per baseband unit, assuming each RRH is single sector.

The above two pictures are from the Small Cells Standardization presentation here.

An old article from Rethink-wireless mentions the following:

This is the central concept of C-RAN, deconstructing the traditional base station to leave a low power unit at the cell site, integrating antenna and radio, while centralizing all the baseband activity and supporting hundreds or thousands of sites flexibly from the cloud. KT calls its LTE approach its Cloud Communications Center (CCC) architecture, and it has been co-developed with Samsung and Intel. The latter is leaping on the opportunity to bring its expertise in servers and data centers to the telco network, and in this case its platforms are integrated with Samsung modems to create a centralized exchange for signals communications processing. This is linked by fiber (essential for C-RAN) to the cell sites.

As seen in vendor strategies like ALU's lightRadio and Nokia Siemens' Liquid Radio, the CCC also harnesses virtualization technology so that the central processing resources can be allocated flexibly according to the peaks and troughs of demand in different sites. Yung Kim, senior EVP head of strategy planning at KT, told TelecomAsia: "For example, at a sports stadium you can dynamically allocate more resources for that area during a game on a millisecond basis." The design also improves coverage at the cell edge, he added, claiming twice the capacity per cell, on average, because of better improved edge management.

The CCC architecture can manage 144 base stations per server and accommodate 1,000 servers in each data center, all them acting as a central processing entity. Most tasks are run on off-the-shelf processors rather than dedicated ASICs, also a key trend to reduce the cost of data networks and to converge the norms of the IT data center with those of telecoms. The performance and power advantages of modern computer processors are now up to the task of massive telecoms networks, believe carriers like KT, hence the intense interest of Intel, although some ARM-based chip vendors like Marvell and Freescale are also pushing from the network into the data center.

Do you have an opinion on the C-RAN architectures in the future? If yes, we would like to hear.

Is 2013 the year of Metrocells?

A recent market market report by Informa for the Small Cell Forum has highlighted the following:

• December last year marked the first launch of a dual mode 3G/LTE femtocell by NTT DoCoMo which allows CS fallback and will be used to promote the migration from 3G to LTE. Orange France has also launched consumer femtocells, diversifying its small cell offerings.
• The small-cell market is growing at a rapid pace: The largest deployments have already reached 1 million active cells. Initial metrocell deployments are taking place while all the operators in several markets now offer femtocells.
• Both SKT and KT have launched LTE small cells for public access in South Korea.
• According to Informa Telecoms & Media’s estimates, the small cell market will generate US$22 billion during 2016, 73% of which will be driven by public area small cells.
• The number of small cells deployed overtook the total number of macrocells between October and November 2012 and consumer femtocells overtook macrocells during February 2013.
• The femtocell market now includes several deployments that reach well into hundreds of thousand units, including Vodafone, Softbank and SFR. Sprint’s deployment reached 1 million units as of October 2012 and analysts estimate that AT&T’s deployment has reached similar numbers.
• As of February 2013, there are 46 commercial services and a total of 60 deployment commitments.

According to this report: The Small Cell Forum released these numbers here at the Mobile World Congress. Gordon Mansfield, chairman of the Small Cell Forum, said 2013 is the "year of public access" small cells, noting that by 2016 public access small cells will drive $16.2 billion in revenue despite the fact that they only make up 4 percent of small cells today.  Mansfield also said 98 percent of mobile operators believe small cells are essential; however, of the 46 operators that have deployed small cells, the majority are larger operators.